C-Bus is a communications protocol based on a seven layer OSI model for home and building automation that can handle cable lengths up to 1000 metres using Cat-5 cable. It is used in Australia, New Zealand, Asia, the Middle East, Russia, United States, South Africa, the UK and other parts of Europe including Greece and Romania. C-Bus was created by Clipsal Australia's Clipsal Integrated Systems division (now part of Schneider Electric) for use with its brand of home automation and building lighting control system. C-Bus has been briefly available in the United States but Schneider Electric has now discontinued sales in the United States. C-Bus is used in the control of domotics, or home automation systems, as well as commercial building lighting control systems. Unlike the more common X10 protocol which uses a signal imposed upon the AC power line, C-Bus uses a dedicated low-voltage cable or two-way wireless network to carry command and control signals. This improves the reliability of command transmission and makes C-Bus far more suitable for large, commercial applications than X10. C-Bus System The C-Bus System can be used to control lighting and other electrical systems and products automatically or via remote control and can also be interfaced to a home security system, AV products or other electrical items. The C-Bus system is available in a wired version and a wireless version, with a gateway available to allow messages to be sent between wired and wireless networks. The wired C-Bus system uses a standard category 5 UTP (Unshielded Twisted Pair) cable as its network communications cable and does not require end of line termination. Clipsal manufactures a specific category 5 cable for use within electrical distribution panels. This cable has a pink outer sheath which is rated to ensure adequate electrical isolation between the mains voltages found in distribution panels and the extra low voltage C-Bus. Outside of distribution panels standard category 5 UTP cable can be used. The category 5 C-Bus network wiring uses a free topology architecture. The maximum length of cable used on a C-Bus network is 1000 metres; however this is easily extended using C-Bus Network Bridges. Up to 100 units can be installed on a C-Bus network and this can also be extended using Network Bridges. The maximum number of C-Bus networks in one installation is 255 (note that this limitation does not apply if a C-Bus Ethernet Interface is utilised,